Reciprocating pumps are utilized to transfer a high viscosity material typically grease or the like from a container such as a drum or barrel to an object of interest which may be a car chassis for example. Such pumps are typically oriented vertically during operation and include a drive motor located outside the container on the container lid, and a reciprocating member operatively connected to the motor to be driven by the motor in a pump chamber. The reciprocating member is placed inside the container and is immersed in the material to be transferred. Because the material transferred by reciprocating pumps is usually of a relatively high viscosity transferral of such material is difficult.
In order to more easily transfer high viscosity materials, conventional reciprocating pumps include a means for pulling or "shoveling" the material from the storage container into the pump. Such means is comprised of a primer element located, proximate the bottom of the drum. The primer element is attached to the reciprocating member and is located adjacent the pump inlet.
During operation of a conventional reciprocating pump, the primer element is moved with the reciprocating member along a linear axis. The primer element is displaced along the linear axis in a first direction, toward the bottom of the material to be transferred, and is then displaced in a second direction, opposite the first direction, toward the surface of the material to be transferred. As the primer element is displaced in the second direction, it acts like a shovel and pulls the medium into the pump.
There are problems with conventional primer elements. Conventional primer elements have a thickness that is significantly less than the diameter or longitudinal dimension of the primer element. Known primer elements resemble a conventional washer that may be used in combination with a bolt. Such known primer elements do not provide a sufficient seal with the pump chamber walls when the reciprocating member is moved in the second direction, permitting material to leak past the primer out of the pump and return to the container. Moreover, the primer does not pull a significant amount of material into the pump. The volume of material transferred by conventional reciprocating pumps is limited by conventional primer elements.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.